Compression-tester for explosive-engines.



J. DESMOND.

COMPRESSION TESTER FOB. EXPLOSIVE ENGINES.

' Patented Jan. 18,1910.

APPLICATION FILED MAR.20, 1908.

iy 7/7 I MAM 41005 UNITED STATES PATENT OFFICE.

' JOHN DESIVIOND, OF CHICAGO, ILLINOIS, ASSIGNOR '10 WILLIAM S. POTWIN, OF

CHICAGO, ILLINOIS.

COMPRESSION -'1ESTER FOR EXPLOSIVE-EN GIN ES.

Specification of Letters Patent.

Application filed March 20, 1908. Serial No. 422,216.

Explosive-Engines, of which the following is a specification.

The invention relates to testing devices for explosive engines and seeks to provide a simple and effective device for testing the compression effected in the cylinder or cylinders of an explosive engine.

Automobiles and the like are usually pro vided with explosive motors having a number of cylinders, frequently as high as four and six cylinders being used.- I'Vith such multiple cylinder engines, it is frequently desirable to ascertain whether or not all the cylinders are operating properly. Moreover, when the engine 1s not running with good eflicienc the trouble may be known to be due to leafr y pistons or leaky valves, but it is frequently impossible to tell in which one or more of the several cylinders the valves or pistons are leaking and it becomes necessary to fix all of the pistons and valves, in order to be sure that the difliculty is remedied.

The present invention provides a simple and efi'ective compression tester which may be readily attached to the different cylinders of the engine, and the amount of compression effected thereby ascertained by rotating the engine shaft. If one or more of the several cylinders do not give the proper amount of compression the trouble is immediately and quickly located.

The invention consists in the features of construction, combinations and arrangements of parts hereinafter set forth, illustrated in the accompanying drawings and more particularly pointed out in the appended claims.

In the drawings, Figure 1 is a sectional view 'of the multiple cylinder engine with the improved tester applied thereto. Fig. 2 is a vertical longitudinal section of the compression tester. Fig. 3 is a partial view in elevation of the same.

The form of ,multiple cylinder engine shown in Fig. 1 comprises two upright cylinders 10 mounted upon the crank casing 11. Pistons 12 in the cylinders are connected by pitmen rods 13 to cranks 14 upon the engine shaft 15, that is journaled in the walls of the crank casing. Each cylinder is provided with an inlet valve 16 and an ex haust valve 17 and also with a threaded opening 18 adapted to receive a suitable igni-' tlon lug. The ignition plug 19, having sparking electrodes 20 and21, is removably screw threaded within the opening 18, as shown in the left hand cylinder in Fig. 1, so that it may be readily removed for cleaning the electrodes and for repairs. The im- Patented Jan.18, 1910.

proved compression tester is provided with a threaded nipple 22 having a reduced, threaded lower end 23, which 1s of standard size and adapted to removabl fit within the ignition-plug opening 18 of the cylinder. In this way,'the ignition plug of a .cylinder may be removed and the compression tester readily and conveniently placed in position.

The nipple 22 of the tester is preferably formed of steel, so that it will not readily become damaged by careless handling, but in order to provide a tight fitting valve seat, a hollow brass plug 24 is snugly fitted within the bore of the nipple. The upper portion of the bore of the ni 'ple 22 is perfectly enlarged and is screw t ireaded as shown and the hollow plug 24 is similarly provided with an enlarged screw threaded upper end.

The plug 24 is provided at its upper end with a valve seat 25, upon which a conical.

valve 26 is snugly fitted. The valve is provided with a guide 27 which depends within the bore of the plug 24, and, at its upper end, the valve has a projecting flange or shoulder 28, which fits within a correspondingly shaped rabbet 29 in the upper end of the plug. When the valve is lifted from its seat by pressure within the cylinder, the shoulder 28 increases the area upon which the escaping gases act and thus insures that the valve will be lifted to afford relief of the gases.

The main body of the testing device consists of a sleeve-like casing 30 which is threaded within the outer end of the nipple 22 above the plug 24. The lower end of this sleeve is cut away or enlarged, as at 31, so that the valve 26 may lift freely from its seat, but preferably the bore of the sleeve is slightly smaller than the valve, so that the latter cannot drop out of the casing and become injured or lost.

A valve stem 32 arranged within the sleeve-like casing 30 is provided at its lower end with a conical head 33, which fits a similarly shaped, central depression upon the upper face of the valve. A thimble 34 threaded over the upper end of the sleeve or casing 30, is provided at its upper end with a hollow projection 35, and t e upper end of the valve stem 32 extends into the bore 36 of the projection 35 and is guided and held in central position thereby. A spring 37 coiled about the stem bears at its ends upon the conical head 33 of the stem and u on the end wall of the thimble 34. The s eeve or casin 36 is provided at its u per end with a re uced, externally threaded portion 38, which engages the internal threads of the thimble 34. Below the threads of the thimble, its bore is enlarged and unthreaded and this lower end portion 39 of the thimble 34 fits over the main body of the sleeve 30. By adjusting the thimble 34 upon the casing 30, the spring 37 may be com pressed to a greater or less extent, so as to var the pressure necessary to lift the valve 26 rom its seat. The lower edge portion 39 of the thimble is rovided with scale marks 40, and themain ody of the sleeve or casing 30 is provided with cooperating scale marks 41, which constitute a Vernier scale to indicate accurately, the pressure of the spring 37, or rather to indicate accurately the pres the thimble 34 is provided with escape ports 42, and an indicating device in the form of a disk .43 is loosely mounted upon the projection 35, and normally closes the ports. To prevent the removal and'loss of the indicating disk 43, the upper end" of the projection 35 is enlarged as shown.

In using the device, one of the ignition plugs of the cylinder is removed and the tester placed in position, as shown in connection with the'right hand cylinder in Fig. l. The engine shaft is then rotated so that a char e of air, or of air and gas will be drawn into the cylinder and com ressed. As the air is compressed it will liit the valve 26 from its seat and will also cause the indicating disk 43 to move up and down. The thimble 34 is then screwed down slowly to increase the pressure of the spring 37 until the point is reached where the com ression eifected in the cylinder is just insu cient to raise the valve 26. This point will be clearly indicated when the disk 43 fails to move from position upon the upper end of the sleeve 34. Then by reading the vernier scale between the lower end of the sleeve 34 and the main body of the casing 30, the maximum pressure effected by the cylinder may be ascertained. If this compression is the desired normal compression for the cylinder, it will indicate that the'piston' packings and the valves of the cylinder are in proper conpressure attained will, of course,

dition. If such is not the case, the maximum the desired normal. By thus testing thevarious cylinders of the motor, the trouble if any exists, may be quickl located an muchtime and expense save in fixing the piston packing rings and the valves.

It is obvious that changes may be made in the details set forth without departure from the essentials of the invention.

Having described my invention what I claimas new and desire to secure by Letters Patent, is: 1. A compression tester for explosive en gines comprising a sleeve-like casing, a relief valve seated in. said casing, a sprin for holding said valve to its seat and a thunble adjustably screw threaded upon the end of said casing and adapted to bear upon the end of said spr' to adjust the pressure thereof, said thim le having esca e ports and said casing having a scale wit which said thimble cooperates to indicate the pressure of said spring, substantially as described.

2. A compression tester comprising a sleeve-like casing having a reduced upper be below end portion, a valve seated in said casing, a

casing, said thimble having escape ports and adapted to bear upon the upperend of said spring to varythe pressure thereof and a Vernier scale upon sald casingand upon the lower end of saidthimble, substantially as described. I

3. A compression tester 'com rising a sleeve-like casing having a threa ed nipple for engaging'a suitable opening in the engine cylinder, a relief valve seated in said casing, a spring in said casing'for'holding said valve to its seat, a thimble adjustably threaded upon the upper reduced end of said casing and having an unthreaded lower end portion fitting over the main body thereof, said thimble having relief ports and adapted to bear upon the upper end of said spring to vary the pressure thereof and a scale upon said casing with which the lower edge of said. casing cooperates to indicate the pressure of said spring, substantially as described.

4. A compression tester for explosive engines comprising a screw threaded nipple adapted to engage a suitable opening in the engine cylinder, a relief valve in said casing, a spring in said casin for holding said valve to its seat, a thimb e adjustably threaded upon the end of said casing and bearing ill sure of said spring and said thimble having relief ports in its end and an indicating device loosely mounted on said thimble over said relief ports, substantially as described.

5. A compression tester for explosive engines comprising a casing having a screw threaded nipple adapted to engage a suit: able opening in the engine cylinder, a relief valve in said casing, a coiled spring in said casing for holding said valve to its seat, a sleeve adjustably threaded upon the end of said casing and adapted to bear upon said spring to vary the pressure thereof, said casing having a scale with which said thimble cooperates to indicate the pressure of saidspring, said thimble having a projection and relief ports on its end and an'indicating disk loosely secured in position upon said projection and normally closing sald ports, substantially as described.

6. A compression tester comprising a screw threaded thimble adapted to engage a suitable opening in the engine cylinder, a relief valve seated in the lower end of said casing and having a depending guide, a valve stem having a conical head engaging the upper face of said valve, a spring coile about said stem and enga ing said head, and a sleeve adjustably threa ed upon the upper end of said-casing and adapted to engage the end of "said spring to vary the pressure thereof, said thimble having a guide for the upper end of said valve stem andsaid casing having a scale with which said thimble cooperates to indicate the pressure of said plug, a stem within said sleeve having a conical lower end engaging a depression in the upper face of said valve, a spring coiled about said stem and engaging said head, a thimble threaded upon the-upper end of said sleeve and adapted to engage the upper end of said spring to vary the pressure thereof,

said thimble having a hollow projection at said valve stem is guided and having relief ports adi'acent said rojectionand an indicating evice loose y secured in position upon said projection and normally closing said ports, said sleeve having a scale with which the lower edge of said thimble coits upper end within which the upper end of 

